The contributor’s responses came from all different fields and thought processes, but there were a few recurring themes. One of the biggest hits was the theory that ulcers were caused by stress—this was discredited by Barry Marshall and Robin Warren, who proved that the bacteria H. pylori bring on the ulcers. Gregory Cochran explains:

One favorite is helicobacter pylori as the main cause of stomach ulcers. This was repeatedly discovered and then ignored and forgotten: doctors preferred ‘stress’ as the the cause, not least because it was undefinable. Medicine is particularly prone to such shared mistakes. I would say this is the case because human biology is complex, experiments are not always permitted, and MDs are not trained to be puzzle-solvers—instead, to follow authority.